1. Field of the Invention
This invention relates to electrical conductors within a substrate which terminate at raised features, and in particular to an arrangement for increasing the density of raised features at the termination site.
2. Description of Related Art
Electrical circuits may be constructed in which a conductor is positioned within a dielectric substrate and terminates at a raised feature which projects beyond the surface of the substrate and is supported by a pad. This provides a means for connection to another electrical component or circuit. A typical circuit assembly, such as a flex circuit or a printed circuit board, will include a multiplicity of such conductors, each with a projecting raised feature at its terminal side. In order to provide enough space for the pads of the raised features, it has been necessary to fan out the conductors at the termination site. Typically, there will be two rows of raised features with the conductors of one row extending between the adjacent raised feature pads of the other row in order to reach the raised features of the former. This spreads out the termination site and results in a relatively low density of contact pads because of the space necessary for the conductors of one row to extend between the pads of the other. When conductors are routed from one side, this limits density to around 60 termination pads per linear inch, that is, two rows of about 30 pads each. This is undesirable in high speed devices in which signal integrity is essential.